In a conventional TFT-OLED pixel circuit, uncontrollable factors of a thin film transistor (TFT) and an organic light emitting diode (OLED) light emitting device, such as process instability, parameter drift, and device aging, results in a change in a current of the OLED, which in turn, results in a uneven light-emitting brightness of a display device including the TFT-OLED pixel circuit.
In order to solve the problem of uneven light-emitting brightness, the conventional compensation method usually detects the voltage/current signals applied to the OLEDs, thereby compensating the voltage/current signals. This compensation method generally solves the problem of uneven light-emitting brightness caused by the change in the characteristics of the driving transistor TFT, but cannot compensate for the problem of uneven light-emitting brightness caused by aging and deterioration of the OLED devices themselves but still occurring when the currents of the OLEDs are made uniform.